Benzothiadiazepine derivatives are described in U.S. Pat. No. 3,453,266 and JP-B-21617/1966, whereas the pharmaceutical actions of these compounds heretofore found are limited only to antispasmodic action, hypoglycemic action, central depressant action, sedative action, hypnotic action, diuretic action, tranquillizer action and antihypertensive action. Although the compounds of the present invention have antiarrhythmic action, local anesthetic action and calcium antagonistic action, nothing has been mentioned about these actions.
An object of the present invention is to provide novel benzothiadiazepine derivatives and pharmaceutically acceptable salts thereof which have excellent antiarrhythmic action, local anesthetic action and calcium antagonistic action and which are very useful as cardiovascular agents such as antiarrhythmic agents and the like.